Resilient stabilizing railway truck assembly



March 18, 1969 A. R. CRIPE 3,433,177

I RESILIENT STABILIZING RAILWAY TRUCK ASSEMBLY Filed March 1, 1966 Sheetof e INVENTOR I AMA/v A? C/Q/PE BY Z W/ Q. X...

ATTORNEY March 18, 1969 A. R. CRIPE 3,433,177

RESILIENT STABILIZING RAILWAY TRUCK ASSEMBLY Filed March 1, 1966 Sheet 2of a March 18, 1969 A. R. CRIPE 3,433,177

RESILIENT STABILIZING RAILWAY TRUCK ASSEMBLY Filed March 1, 1966 sheetof e March 18, 1969 A. R. CRIFE Filed March 1, 1966 Sheet 4 l V- L-March 18, 1969 A. R. CRIPE 3,433,! 77

RESILIENT STABILIZING RAILWAY TRUCK ASSEMBLY Filed March 1, 1966 Sheet 5of 6 March 18, 1969 R, CRIPE 53,433,177

RESILIENT STABILIZING RAILWAY TRUCK ASSEMBLY Filed March 1, 1966 Sheet 6of s fie. 10

iii? -Il1 fcJZ United States Patent 3,433,177 RESILIENT STABILIZINGRAILWAY TRUCK ASSEMBLY Alan R. Cripe, Richmond, Va., assignor to UnitedAircraft Corporation, East Hartford, Conn, a corporation of DelawareFiled Mar. 1, 1966, Ser. No. 530,960

11.8. Cl. 105199 12 Claims Int. Cl. B61f 5/26, 3/04, 1/06 ABSTRACT OFTHE DISCLOSURE A railway truck assembly is described which incorporatesindependently-oscillatory side frames which directly support a bolsteron which in turn a vehicle body is resiliently mounted throughtorsilastic mountings which allow controlled rolling of the body. Agimbal member held captive between the side frames serve as the pivotpoint for the bolster and the side. frames and means, particularlypillow blocks, are provided between the confronting surfaces of the sideframes and the bolster for accommodating a relative rocking motiontherebetween.

This invention relates to railway vehicle truck assemblies forlightweight high performance articulated trains.

The operating parameters specified for the more advanced lightweightpassenger trains contemplate normal operating speeds nearly double thoseof conventional trains. At these higher speeds even minor trackirregularities and discontinuities are magnified into major sources ofpassenger discomfort and equipment stress. To minimize the adverseeffects of high speed travel, generous use is made of flexible andresilient mountings and connections to eliminate, where possible, alldirect transmission routes for noise and vibration between their sourceand the vehicle interior to isolate the passenger therefrom. Suchpractices inherently allow considerable freedom of movement at thevarious connections within limits established by the degree ofresilience provided in the mountings.

Further, in most truck assemblies many of the various componentscomprising the assembly are designed to allow relative movementtherebetween independent of the other components. In some constructions,for example, the side frames, which are the basic load-carrying memberssupported on the rotating axles, are permitted to oscillate in avertical plane independently of each other and independently of thevehicle. Accordingly, each side frame is allowed to assume its own angleof attack in a vertical plane as a function of the angle assumed by therail over which it rides. As a result, the effects of a roadbedunevenness at one rail are not transmitted to the entire assembly.

Still further, truck constructions necessarily allow a pivotal movementof a portion of the truck in a horizontal plane around a given verticalaxis. The necessity for such pivotal movement of the truck with respectto the vehicle body is evident since the truck always turns into or outof a curve in the track at a different rate than that of the vehicleitself.

At very high train speeds, however, truck stability becomes a majorproblem. While the hereinbefore discussed freedom of movement isadvantageously incorporated into a truck assembly, it must neverthelessbe rigidly controlled so that the geometry of movement is confined infixed planes.

One of the principal objects of my invention, therefore, is to provide alightweight railway truck assembly which is characterized by a highdegree of freedom of movement between its various components but which3,433,177 Patented Mar. 18, 1969 confines the geometry of movement topredetermined planes to provide stability of operation at high trackspeeds.

A current design of a lightweight passenger train incorporates anadvanced suspension system wherein the cars are caused to bank on curvesin a manner similar to aircraft flight. These trains, for this purpose,utilize an improved version of the radially-guided, single-axle,pendulum suspension system shown and described in my prior Patent2,954,746. In this system a single axle mounted between the cars is usedto provide support for the ends of both of the abutting car bodies andthe axle is steered to maintain it perpendicular to the track at alltimes. Accordingly, the wheels always assume a zero angle of attack withrespect to the rail.

A powered dome car is provided at each end of this truly bidirectionaltrain, each dome car carrying at least part of the propulsion andauxiliary power for the train, and being adapted additionally totransport passengers therein. Dual-axle powered trucks of an advanceddesign are used at the free end of each ofthese dome cars as supporttherefor, the articulated end being provided with the single axle,pendulum-type support as hereinbefore discussed. Because of the pendulumsupport at the articulated end of the car, this end is adapted to bankon curves. This tendency would be resisted if a conventional truckassembly were incorporated in the train design since the conventionaltruck assembly is specifically designed to oppose any rolling movementof the car body. It is, therefore, necessary to incorporate in the truckassembly means for encouraging a controlled roll of the car body about alongitudinal axis whereby the desired banking on curves may be achievedand to make the truck system compatible with the suspension systeminstalled intermediate each of the cars. This is particularly importantin this train since passengers will be carried in the powered orlocomotive units.

Another object of my invention, therefore, is to provide a railway truckassembly which permits controlled rolling of the car in which it isinstalled whereby the car is caused to bank on curves.

The weight of the car body is taken through air springs and theirsupporting structural members to a bolster which is in turn verticallysupported on the respective side frames. A substantial contact area isprovided between the bolster and its confronting side frame and usuallya sliding surface is provided therebetween since the bolster must slideon the side frame as the train enters a curve and a portion of the truckassembly rotates beneath it. However, since the side frames mayexperience limited rotation in a vertical plane beneath the bolster asthe wheel negotiate irregularities in the track, their confrontingsurfaces are caused to assume an angle of attack with respect to oneanother. In'other constructions this is compensated for to a limitedextent through the use of a resilient slide support positioned in theside frame beneath an appropriate bearing surface. In theseconstructions, however, a greater wearing force is transmitted to oneend of the bearing surface than the other. Further, because this forceis carried over a smaller bearing area, a greater frictional factor iscreated which resists the sliding movement of the bolster at one side ofthe assembly. At very high speeds this fore-and-aft weight transfer atthe bearing surface at one side of the assembly may result in shimmy ofthe truck.

It is a further object of my invention to provide means whereby therelative movement between the bolster and the side frames isaccommodated without opening a gap therebetween and without causinglocalized wear in the bearing surfaces through a localized fore-andeftshift ing of the load thereon. This is accommplished through use of acaptive pillow block, the bottom surface of which is adapted to slide onthe upper side of the side frame, and the upper surface of which isformed with a concave oavity which engages a cooperating convexprojection on the bottom of the bolster. Accordingly, although thepillow block may rotate in a vertical plane together with the s ideframe at the curved contacting surfaces of the cavity and matingprojection on the bolster, the sliding surfaces on the bottom of thepillow block and the side frame are always maintained in the same plane.In this construction, therefore, the desired geometry of movement is-zchieved but rigidly controlled to eliminate chatter between the partsand excessive wear.

A further object of my invention is generally to improve theconstruction and performance of lightweight railway trucks.

These and other objects and advantages of my invention will be set forthin the following description or will be evident therefrom or frompractice of my invention.

In the drawings:

FIG. 1 is a perspective view of a preferred embodiment of the truckassembly;

FIG. 2 is a view of the truck assembly taken in elevation;

FIG. 3 is an end view of the truck assembly;

FIG. 4 is a view similar to that of FIG. 3 except that the forward wheelassembly, gearbox and braking mechanisms have been removed to moreclearly show the positions of the various cooperating elementsassociated with the pivotal movement of the truck.

FIG. 5 is a fragmentary exploded view of the pillow block constructionand arrangement;

FIG. 6 is an exploded View of a gimbal and pivot pin arrangement forminga swivel joint between the bolster and side frame-axle unit.

FIG. 7 is a side view of the torque arm connecting the axle mountedreduction gear to a side frame at a cushioned connection;

FIG. 8 is a fragmentary top view of the torque arm and its connectionsto the side frame;

FIG. 9 is a somewhat schematic illustration of yaw damping means tominimize high frequency pivotal oscillations of the running gear;

FIG. 10 is a somewhat schematic representation of a roll damping andbiasing piston arrangement installed between the bolster and thelaterally translating spring support arms;

FIG. 11 is a side view of the piston arrangement of FIG. 9;

FIG. 12 is a perspective view of an alternative lateral link structureproviding support in shear for the air spring.

As shown in FIGS. 1, 2 and 3, the truck is made up of two longitudinallyspaced side frames, 2 and 4, each having an inwardly-directedprojection, 6 and 8 respectively, extending toward the verticalcenterline of the truck assembly. A pair of wheel-axle assemblies, 10and 12, are mounted in bearings provided at each end of the respectiveside frames, the mounting being effected to prevent any substantiallongitudinal or transverse movement of the side frames with respect toone another but in resilient bushings as hereinafter discussed. Sincethe side frames are the basic load-carrying members of the assembly,they are necessarily of substantial rigidity and are provided with aflat upper surface on which the weight of the vehicle may be slidablysupported.

The wheel-axle assemblies constitute the primary fixed connectionsbetween the respective side frames, and the side frames are free torotate, to a limited extent, in a vertical plane, independently of oneanother. This capability is permitted through the use of a resilientaxle bearing mounting which is not shown but which includes a resilientbushing surrounding a roller bearing to permit a limited floating of thebearing within the mounting. This concept is described in my copendingapplication Serial 4 No. 516,898, now Patent Number 3,382,017, issuedMay 7, 1968, and constitutes no part of the present invention except asa preferred element of the assembly. The resilient bushing furtherserves to isolate the vehicle from the high frequency vibrationsgenerated by the passage of the metal wheels over the rails at highspeed.

Power is individually supplied to each of the axles through axle-mountedgearboxes, 14 and 16, which receive power through Cardan shafts, 18 and20, from a source external to the truck assembly.

A transverse bolster 22, on which the vehicle is suspended, is providednear the centerline of the truck, the ends of the bolster extendingacross the respective side frames. The bolster is connected to the sideframe-axle subassembly in a pivotal connection whereby this subassemblyis permitted to assume an angle of attack in a horizontal planeindependent of that assumed by the vehicle itself. For this purpose, andas most clearly seen in FIGS. 4 and 6, the side frame projections 6 and8 are terminated in flat, mutually-opposing surfaces, 30 and 32, aconsiderable distance from the longitudinal centerline of the truck.Cylindrical cavities, 34 and 36, are formed in the flat surfaces on acommon axis with the cavity openings facing each other, and acentrally-located gimbal 38 is positioned therebetween. The gimbal 38includes cylindrical end portions 40 and 42 which are closely androtatably fitted into the respective cavities. In this construction, theplanes of rotation of the side frames are always held parallel and theirrotation in a vertical plane is effected about a single transverse axiscommon to both side frames. The gimbal also includes a thickened centerportion 44 in which a vertical opening 45 is provided which is adaptedto closely receive a pivot pin 46 which is suitably connected to thebolster, As assembled, the swivel member is held captive in and betweenthe side frame projections and prevents any closure movement betweenthem. Accordingly, the respective side frames 2 and 4 are permitted torotate around the cylindrical end portions of the gimbal independentlythereof and independently of each other, but only about a singletransverse axis common to both side frames. Similarly, the sideframe-axle subassembly, including the swivel member, is permitted torotate in a horizontal plane around the pivot pin 46. It is, of course,contemplated that appropriate bearing surfaces will be provided in theusual manner between all of the relatively movable surfaces.

The bolster 22 is provided with a vertically-directed opening which isaligned with the opening in the swivel member, the pivot pin 46extending through both of these openings. The braking, acceleration andother longitudinally-directed loads are taken through this pivotalassembly but no vertically-directed vehicle loads are imposed thereon,the Weight of the vehicle being taken through the bolster directly tothe side frames as hereinafter described.

The bolster 22 is provided with a downwardly-directed convex projection50 at each end thereof in the vertical plane of the side frames. Whilethis has been illustrated in FIGS. 4 and 5 as being effected by means ofa bolted detail aflixed to the bottom of the bolster, the requisiteprojection may be formed integral with the bolster structure. Theprojection 50 engages in a mating concave cavity 52 which is provided ina pillow block 54 held captive between the bolster and the top of theconfronting side frame. The pillow :block is adapted to slide on theside frame as the running gear pivots beneath the bolster and, for thispurpose, a slidable surface 56 of Teflon or other material ofpredetermined frictional characteristics is preferably positionedbetween the confronting surfaces of the pillow block and the side frameon which it rests. The convex projection 50 has a slightly greatervertical dimension than that of the concave cavity 52 whereby the sideframe and mounted pillow block may rock in a vertical plane with respectto the bolster as the wheels on one side of the truck assembly negotiateirregularities in the track.

In other constructions where the bottom of the bolster rests directly onthe side frame, a gap is opened between the bearing surfaces as the endsof side frames oscillate vertically, unless provision has been madetherefor. In some constructions the side frame bearing surface isaffixed to a resilient slide support which is embedded in the topsurface of the side frame. In my construction, the bottom surface of thepillow block is always maintained in the same plane as that of the flatsurface on the top of the side frame and no localized wear is caused inthe respective bearing surfaces, the relative rocking motion beingaccommodated at the contacting semispherical surfaces within the pillowblock cavity.

While the pillow block has been described in connection with a preferredconstruction, there is, of course, no reason why the cavity cannot beprovided in the bolster and the projection on the pillow block toaccommodate the rocking motion hereinbefore described. Similarly thecontacting rocking surfaces need not be semispherical nor need they beprovided between the bolster and the pillow block. In an alternativeconstruction, the pillow block may be made slidable on the bolster, therocking motion being accommodated at curved surfaces provided betweenthe bottom of the pillow block and the top of the side frame.

In order to reduce truck shimmy resulting from high frequency hunting ofthe pivotal portion of the truck assembly at very high speeds, at yawdamper is preferably provided in the assembly. Such a yaw dampingconstruction is shown somewhat schematically in FIG. 9. Alongitudinally-directed plate 70 of substantial rigidity is provided onthe bolster 22. A plurality of hydraulic cylinders 71 and 72, orientedtransverse to the truck assembly, are atiixed in a common pivotalconnection 73 to the plate 70 at one end and to the respective sideframes 2 and 4 at their other ends, the movable hydraulic pistons 74 and75 internal of each cylinder, translating laterally in response tohorizontal movements of the bolster with respect to the side frames.Communication between the chambers formed within each of the cylindersby the pistons is effected through conduits 76 and 77 and variableorifices 78. The orifices are made variable as a function of speed by asignal from speed sensors 80. As the speed of the vehicle increases, theorifice size is reduced thereby offering greater resistance to the flowof fluid through the connecting conduits, providing in turn a greaterstabilizing force between the bolster and the pivotal portion of thetruck assembly. In actual practice it is anticipated that no dampingwill be required at speeds under 60 miles per hour and, therefore, theorifice will be fully open at this speed level.

Each of the axles is furnished with an axle mountedreduction gearthrough which power is transmitted to the axle and to the drivingwheels. Power to the forward wheel-axle assembly 10 is provided byCardan shaft 18 which penetrates the bolster 22 through a suitablehorizontal opening 79 (FIG. 6) or 81 (FIG. 4) provided therein. Sincethe gearboxes are unsupported except by the rotating shaft, means mustbe provided to accommodate the torque loads imposed on the gearbox aspower is applied during acceleration. For this purpose, and as best seenin FIGS. 7 and 8 a torque arm 80 is bolted to the reduction gear 14 atone side and to the side frame 2 at the other end of the arm. Themounting of the torque arm to the side frame is resiliently effected inthe conventional manner utilizing a plurality of rubber bushings 82surrounding a flange 84 affixed to the side frame and held captivebetween a metal washer 86 which is fixed to bolt 88 and a metal washer90 Which is held in place by nut 92. In this manner rotation of thegearbox about its axle is prevented. Since the side frames oscillate indilferent modes and independently of each other,

all torque-compensating connections from the gearbox must necessarily bemade to a single side frame.

The braking mechanism carried by the truck is conveniently attached tothe side frames. I prefer to employ both a magnetic track brake 94 andtread brakes 96 and 98 on both sides of the truck. The construction andoperation of those elements are well known in the art and furtherdescription relative thereto is, therefore, not included.

The resilient spring assembly by which the vehicle is supported from thebolster is preferably adapted to permit limited and controlled lateraltranslation of the vehicle body with respect to the running gear. Toaccomplish this translation and impart a bank to the vehicle on curves,two inwardly and upwardly directed spring support arms, 100 and 102, aremounted to the bolster in torsilastic bearings, 104 and 106, positionedat each end of the bolster. The torsilastic bearings are suitablyattached to the ends of the bolster in a fore-and-aft orientation onsupporting trunnions, and the support arms are affixed thereto to permitthe translation of their free ends in a plane perpendicular to thelongitudinal axis of the vehicle. The torsilastic bearings cause thevehicle body, through the action of the support arms, to assume a normalcentered position. However, upon the application of centrifugal force tothe lower part of the car as the vehicle rounds a curve or any otherforce tending to rotate the car about its longitudinal centerline, thefree ends of the support arms move outward with respect to the curve. Inso doing, the extremity of the free end of the inner support arm, 102for example, moves toward the center of the truck and downward, carryingthe inner side of the vehicle body with it. The free end of the outerarm, 100 for example, will straighten causing the outer side of the carto rise. By this concerted action of the arms the vehicle will be causedto bank. With the car in the banked position the respective torsilasticbearings will be placed under a torsion force which will restore the carto its centered position once the centrifugal force is removed.

Longitudinal loads are transmitted to the vehicle body through a pair ofexpandable drag links and 112 which are connected at one end to the endof the bolster and extend fore-and-aft therefrom. The links areuniversaljointed and are adapted at their free end to a connection withthe vehicle body. While only one pair of drag links has been illustratedit will be understood that a similar drag link structure is provided atthe other side of the truck assembly.

The drag link construction is basically the same as that taught in myprior Patent 2,935,031 and in operation confines the movement of thebolster with respect to the vehicle to a fixed vertical plane normal tothe longitudinal axis of the vehicle. The body of the railway car maymove freely in a vertical direction with respect to the bolster as aresult of the compression and expansion of the pneumatic spring system.It may similarly move in a transverse direction, as hereinbeforediscussed, as the car banks. Despite this freedom of movement, however,the body cannot move longitudinally with respect to the bolster.

In some installations means are incorporated in the assembly for dampingthe roll of the vehicle. Further, it may be advisable to provide meansfor biasing the vehicle laterally to compensate for variable forcestending to roll the car body as, for example, during operation of thetrain in a strong cross-wind. Such a roll damping and biasingconstruction is illustrated in FIGS. 10 and 11.

At each side of the assembly there is provided between the bolster 22and the spring support arm 102 a damping piston and a biasing element122. The damping piston, which in operation is functionally similar tothe yaw clamping cylinders previously described, allows a lateraltranslation of the car body only upon the application of a sustainedlateral force and thus eliminates any unwanted roll resulting frommomentary laterally acting forces due mainly to trackage irregularities.By making the orifice 124 in the conduit 1.26 between the pistonchambers variable as a function of speed, it is possible to maintain aconstant roll rate at all train speeds. In an alternative arrangement,the operation of the roll damper could be made at the option of theengineer whereby all roll could be prevented during passage of the trainthrough close quarters as, for example, between closelyabutting highlevel station platforms.

The operation of the biasing element is relatively evident. From asource 128 air is provided to the chamber formed beneath the moveablepiston 130 at varying pressures depending upon the level of the sideforce to be equalized. It may be operable from the cab of the poweredunit or automatically and may, in addition to the damping means, beutilized to prevent unwanted roll of the car body in a given directionif desired.

Lateral links, 108 and 110, are rotatably attached to the free end ofthe support arms at each side of the assembly and additionally connectedto the vehicle body. The upper surface of each of the lateral linksfurnishes a mounting platform for the air springs 112 and 114 whichresiliently support the vehicle body 116 in recesses provided therein attransversely spaced locations. The basic purpose of the lateral links isto maintain the base of the air spring in relatively fixed verticalalignment with the upper end of the spring to prevent the imposition ofany shear loads upon the spring itself.

Although a single wishbone lateral link structure has been illustratedin the preferred embodiment, the same function may be provided by othermeans. An alternative construction providing shear support for thepneumatic spring is illustrated in FIG. 12. In this construction,lateral links, 140 and 142, at the bottom of the spring and similarlinks, 144 and 146, at the top of the spring are used to absorb theaxial and transverse forces acting thereon while permitting freeoperation of the spring on a fixed vertical axis. The individual linksextend in a generally horizontal plane from a common attachment at thespring to a spaced attachment with the vehicle body at their free ends.Accommodation for the requisite vertical movement of the spring iseffected through the use of resilient mountings at both ends of thelinks in the conventional manner and the weight of the vehicle is takenthrough the upper arms 148 and 150, the springs, and the torsilasticspring support arm 102 as previously discussed.

A plurality of upstanding resilient supports 118 are provided in thespace between the upper surface of the lateral links and the vehiclebody to provide a backup support for the vehicle in the event of amalfunction in the air spring. These supports are formed to aconsiderable height and are preferably of varying resilience to furnishvarious degrees of support to the vehicle as a function of its downwardmovement.

While my invention has been primarily described in connection with aparticular preferred embodiment, other modifications and alterations tothe various elements of the assembly will be obvious from the teachingsherein. The present embodiments are, accordingly, intended to beillustrative only.

I claim:

1. A truck assembly for a railway vehicle comprising:

a pair of transversely spaced rigid side frames each having aninwardly-directed projection of substantial thickness, the respectiveprojections terminating in mutually-opposing, transversely-spacedsurfaces near the transverse centerline of the truck. each of theopposing surfaces having a cylindrical cavity therein, the cavitieslying on a common axis,

a pair of longitudinally-spaced wheel-axle assemblies rotatably andresiliently mounted in the side frames, the wheel-axle assemblies andassociated mountings maintaining the side frames in positionlongitudinally and transversely of one another,

a gimbal held captive between the opposing surfaces of the side frameprojections, the gimbal having cylindrical end portions closely androtatably positioned in the respective cavities in the side frames andan enlarged central portion having a vertical opening therethrough,

a transverse bolster extending between and over each of the side framesand slidably supported thereon, the bolster having a downwardly directedpivot pin closely and rotatably received in the opening in the gimbal,

a plurality of drag links connected to the respective ends of thebolster and having connecting means at their free ends for attachment tothe vehicle to permit free vertical and transverse movement between thebolster and the vehicle in a fixed plane perpendicular to thelongitudinal axis of the vehicle,

an upwardly directed spring assembly connected to the bolster at eachend,

and means for connecting the free end of the spring to the vehicle.

2. A truck assembly for a railway vehicle comprising:

a pair of transversely-spaced side frames,

a pair of longitudinally-spaced wheel-axle assemblies rotatably mountedin the side frames, the mountings preventing substantial longitudinaland transverse movement of the side frames with respect to one another,

a transverse gimbal member rotatably mounted in the side frames and heldcaptive therebetween, the gimbal member having a vertical openingtherethrough near the vertical centerline of the truck,

a transverse bolster extending between and over each of the side frames,the bolster having a downwardlydirected pivot pin closely and rotatablyreceived in the opening in the gimbal member and a semispherical area onits bottom side at each end thereof in the vertical plane of the sideframes,

a pillow block held captive between the confronting surfaces of thebolster and the side frame at each side of the truck, each pillow blockhaving a flat lower surface slidably supported on the upper surface ofthe respective side frame and having a semispherical surface formed inits upper side which mates with the corresponding semispherical surfaceon the bottom of the bolster, the weight of the vehicle being takenthrough the bolster, the mating semispherical surfaces and the pillowblock to the side frames, a rocking motion being permitted between thebolster and the pillow block at the semispherical surfaces,

a plurality of drag links connected to the respective ends of thebolster and having connecting means at their free ends for attachment tothe vehicle to permit vertical and transverse movement between thebolster and the vehicle in a fixed plane perpendicular to thelongitudinal axis of the vehicle,

a spring assembly at each side of the vehicle connected to the bolsterat its end,

and means for connecting the free end of the spring to the vehicle.

3. A truck assembly according to claim 2 in which:

a yaw damper is provided between the bolster and at least one of theside frames to reduce high frequency hunting of the running gear.

4. A truck assembly according to claim 3 in which:

each spring assembly includes an air spring and supporting structuretherefor which permits controlled lateral movement of the vehicle bodywith respect to the bolster to promote roll of the vehicle about alongitudinal axis as a result of centrifugal force when the vehiclenegotiates a curve.

5. A truck assembly according to claim 3 in which each spring assemblyincludes:

a torsilastic arm attached to the end of the bolster and extendingupwardly and normally inwardly there from, the torsilastic arm beingmovable at its free end vertically and transversely in a planeperpendicular to the longitudinal axis of the truck assembly, and anupwardly-directed air spring aflixed to the free end of the torsilasticarm.

6. A truck assembly for a railway vehicle comprising:

a pair of transversely-spaced rigid side frames each having aninwardly-directed projection of substantial thickness, the respectiveprojections terminating in mutually opposing transversely-spacedsurfaces near the transverse centerline of the truck, each of theopposing surfaces having a cylindrical cavity therein, the cavitieslying on a common axis,

a pair of longitudinally-spaced wheel-axle assemblies rotatably andresiliently mounted in the side frames, the wheel-axle assemblies andassociated mountings maintaining the side frame in positionlongitudinally and transversely of one another,

a gimbal held captive between the opposing surfaces of the side frameprojections, the gimbal having cylindrical end portions closely androtatably positioned in the respective cavities in the side frames andan enlarged central portion having a vertical opening theretthrough,

a transverse bolster extending over each of the side frames, the bolsterhaving a vertical opening therethrough on an axis coinciding with thatof the opening provided in the gimbal and having a semispherical surfaceprovided at its bottom side in the vertical plane of the side frames,

a pillow block held captive between the confronting surfaces of thebolster and the side frame at each side of the truck, each pillow blockhaving a fiat lower surface slidably supported on the upper surface ofthe side frame and having a semispherical surface provided in its upperside with which the corresponding semispherical surface on the bolstermates to permit relative rocking motion between the pillow block and thebolster, the weight of the vehicle being carried through the bolster,the mating semispherical surfaces and the pillow blocks to the sideframes,

a pivot pin closely-received in the openings provided in the bolster andthe gimbal, the side frames and connected wheel-axle assemblies beingpermitted to pivot with respect to the bolster,

means for maintaining the bolster in a fixed plane longitudinally of thevehicle,

and means for resiliently supporting the vehicle from the bolster topermit controlled lateral and vertical movement of the vehicle body withrespect to the bolster.

7. A truck assembly according to claim 6 in which:

the semispherical surface provided on the bottom side of the bolstercomprises a convex projection thereon,

and the semispherical surface provided in the upper side of the pillowblock comprises a concave cavity into which the convex projection on thebolster is closely fitted.

8. A truck assembly according to claim 7 in which the means formaintaining the bolster in a fixed plane longitudinally of the vehicleincludes:

a pair of expandable drag links connected to the free end of bolster ateach side of the assembly and extending fore and aft therefrom, the freeend of each drag link having means for connecting the respective draglinks to the vehicle to maintain movement of the vehicle body withrespect to the bolster in a vertical plane perpendicular to thelongitudinal axis of the vehicle.

9. A truck assembly for a railway vehicle comprising:

a pair of transversely spaced side frames, each having a bearing areaprovided in its upper surface near its longitudinal midpoint,

a pair of longitudinally-spaced wheel-axle assemblies rotatably mountedin the side frames, the mountings fixedly positioning the side framestransversely of one another,

a gimbal rotatably mounted in the side frames near their longitudinalmidpoint and extending therebetween, the gimbal being rotatable in avertical plane parallel to the longitudinal axis of the truck assembly,

a transverse bolster extending over each of the side frames andpivotally connected to the gimbal, the bolster having a bearing areaprovided in its bottom surface in the plane of the side frames,

a pillow block held captive between the bearing areas on the bolster andthe side frame at each side of the truck, each pillow block having aflat surface slidably contacting one of the bearing areas and a curvedsurface mating with a cooperating curved surface provided in the otherbearing area to permit a longitudinal rocking motion therebetween, theWeight of the vehicle being taken through the bolster and pillow blocksat the curved surfaces to the side frames,

a plurality of drag links connected to the respective ends of thebolster and having connecting means at their free ends for attachment tothe vehicle to permit vertical and transverse movement between thebolster and the vehicle in a fixed plane perpendicular to thelongitudinal axis of the vehicle,

a torsilastic bearing connected to the bolster at each end thereof,

a support arm attached to each torsilastic bearing and biased thereby,each support arm normally extending upwardly and inwardly from thetorsilastic hearing and being movable at its free end in a planeperpendicular to the longitudinal axis of the vehicle,

a vertically-oriented spring pivotally attached to the free end of eachsupport arm,

means for attaching the free end of each spring to the vehicle,

and means for retaining the respective ends of each spring on a commonaxis to prevent the imposition of shear loads thereon.

10. The truck assembly of claim 9 in which:

a yaw damper is provided between one end of the bolster and at least oneof the side frames to reduce high frequency hunting of the side frameand connected wheel-axle assemblies.

11. The truck assembly of claim 10 in which the means for maintainingthe respective ends of each spring on a common axis includes:

a lateral link structure attached at one end to the bottom of thespring, the other end of the link structure having connecting means forattachment to the vehicle to maintain the bottom of the spring in afixed position longitudinally and transversely of the vehicle.

12. A truck assembly for a railway vehicle comprising:

a pair of transversely spaced rigid side frames each having aninwardly-directed projection of substantial thickness, the respectiveprojections terminating in mutually-opposing, transversely-spacedsurfaces near the transverse centerline of the truck, each of theopposing surfaces having a cylindrical cavity therein, the cavitieslying on a common axis,

a pair of longitudinally-spaced wheel-axle assemblies rotatably andresiliently mounted in the side frames, the wheel-axle assemblies andassociated mountings maintaining the side frames in positionlongitudinally and transversely of one another,

a gimbal held captive between the opposing surfaces of the side frameprojections, the gimbal having cylindrical end portions closely androtatably positioned in the respective cavities in the side frames andan enlarged central portion having a vertical opening therethrough,

a transverse bolster extending between and over each of the side framesand slidably supported thereon,

1 1 the bolster having a downwardly directed pivot pin closely androtatably received in the opening in the gimbal, means for accommodatinga limited relative rocking motion between the confronting surfaces ofthe bolster and the respective side frames over a uniformly-loadedbearing area, plurality of drag links connected to the respective endsof the bolster and having connecting means at their free ends forattachment to the vehicle to permit free vertical and transversemovement between the bolster and the vehicle in a fixed planeperpendicular to the longitudinal axis of the vehicle, an upwardlydirected spring assembled connected to the bolster at each end, andmeans for connecting the free end of the spring to the vehicle.

References Cited UNITED 10 ARTHUR L. LA POINT, Primary Examiner.

HOWARD BELTRAN,

Assistant Examiner.

US. Cl. X.R.

